Male reproductive System Flashcards
What are gametes?
Sexual cells
When the two types of gametes combine they form a ___
zygote-fertilized egg
gametes produced by males are called
Sperm (spermatozoon)
Gamets produced by females are called?
Eggs (ovum)
Females are lacking a ___ chromosome
Y
The functions of the male reproduction system is to___
produce sperm and introduce it into the female body
The function of the female reproduction system is to ___
receive sperm from male, provides for the union of gametes, harbors fetus, and nourishes offspring
The male copulatory organ is the___
penis
The female copulatory organ is the___
Vagina
What are the male primary sex organs?
Testies
What are the female sex organs?
Ovaries
What are secondary sex organs?
Organs other than gonads that are necessary for reproduction
What are the female secondary sex organs? their collective function?
- Uterine tubes
- uterus
- vagina
- collectively receive sperm and harbor developing fetus
What are the male secondary sex organs? their collective function?
- system of ducts,
- glands;
- penis delivers sperm cells
What are secondary sex characteristics?
Features that distinguish the sexes and influence mate attraction
When do secondary sex characteristics develop?
during puberty
What are secondary sex characteristics unique to males?
- Facial hair
- coarse visible hair on torso and limbs
- muscular physique
What are secondary sex characteristics unique to females?
- Distribution of body fat
- breast enlargement
- Hairless appearance of the skin
Our cells contain ___ pairs of chromosomes
23
How many pairs of chromosomes determine sex?
1 pair
XX chromosomes produce___
XY chromosomes produce ____
- Females
- Males
All eggs carry a ___ chromosome
Sperm carry both X and Y and a ___ ratio
- X
- 50/50
Sex of a child is determined by____
the type of sperm that fertilizes the egg
How long into the pregnancy do gonads begin to develop?
5-6 weeks
What gene found in males initiates the development of testes?
the SRY gene
What point during development does the male embryo begin producing testosterone?
8-9 weeks
Female development of a fetus occurs whenever the is an absence of ___ not because of the presence of ___
- Androgen hormones
- Estrogen
The glands of the penis/clitoris form from the ___ in embryonic development
Genital tubercle
The glands of the body of the penis/labia minora form from the ___ in embryonic development
Urogenital folds
The glands of the scrotum or labia majora form from the ___ in embryonic development
Labioscrotal folds
The penis is homologous to the ___
Clitoris
The scrotum is homologous to the___
Labia majora
At what point during development are the genitalia distinctly formed?
week 12
Where do gonads initially develop?
High in the abdominal cavity
Where do male gonads migrate to?
the scrotum
Where do female gonads migrate to?
The pelvic cavity
What is gubernaculum?
embryonic connective tissue cord extending from gonad to pelvic cavity floo
What is the vaginal process?
fold of peritoneum that extends into the scrotum
What is the Inguinal canal?
: pathway of low resistance through the groin created by gubernaculum and vaginal process
Where is the most common site of hernias in males?
the inguinal canal
How early does the decent of the testes begin?
as early as 6 weeks
What point during development do the testes finish their descent into the scrotum?
Month 7
The external genitalia of males are___
the penis and scrotum
What is the medial seam on scrotum surface that marks location of median septum
Perineal raphe
What temperature does sperm production occur at?
35 degrees Celsius
What three mechanisms regulate the temperature of the testes?
- The cremaster muscle:contracts to draw testes up
- The dartos fascia:wrinkles to hold agains warm body
- Pampiniform plexus: remove body heat via venous surface area
The testes are covered laterally by the___
Tunica vaginalis
What is the white fibrous capsule on the testies?
The tunica albuginea
Connective tissue divides the testes into ______
200-300 wedge shaped lobes
After sperm are produced in the seminiferous tubules where does it go next?
Through the rete testis
What allows sperm to flow from the testes
Fluid produced by nurse cells not the flagella on the sperm
Sperm only swim___
when they are outside of the male reproductive tract
What are the two main cell types within the seminiferous tubules?
- A germinal epithelium of germ cells becoming sperm
- nurse cells
What is the function of nurse cells within the seminiferous tubules?
- Protect germ cells
- promote development of germ cells
- Provide nutrients, waste removal, growth factors
- produce fluid that allows sperm to be transported from the tubules
What cells within the testes produce testosterone?
the interstitial endocrine cells
What are the two main functions of the epididymis?
- Site of sperm maturation
- site of storage
What type of innervtion does the Ductus deferens have?
sympathetic
What are the three male accessory glands
- The seminal vesicles
- The prostate
- the bulbourethral glands
What is the function of the seminal vesicles?
Forms 60% of semen
What is the function of the prostate?
Produces a thin milky secretion that makes up 30% of semen
What is the function of the bulbourethral glands?
- Produce pre-ejaculate during sexual arrousal
- This neutralizes the acidity of the urethra
What is the average age of puberty in males?
10-12 years
What is the average age of puberty in females?
8-10
What defines adolescence?
period from onset of gonadotropin
secretion and reproductive development to when a person attains full adult height
What defines puberty
first few years of adolescence, until the
first menstrual period in girls or the first ejaculation
of viable sperm in boys
What triggers the onset of puberty in males?
GnRH begins to be secreted in late childhood once the hypothalamus matures
What is the hormone pathways that results in the beginning of testosterone production?
- GnRH stimulates the release of LH (also know as interstitial cell-stimulating hormone(ICSH))
- This stimulates interstitial cells to produce testosterone
What hormone pathway leads to the production of sperm?
- GnRH also stimulates FSH
- FSH causes nurse cells to release androgen binding protein
- Testosterone stimulates spermogenisis in the presence of androgen binding protein
How do nurse cells reduce sperm production without reducing testosterone?
- Via the hormone inhibin
- inhibin inhibits FSH thus reducing the amount of ABP produce by the nurse cells
How do testosterone levels regulate themselves?
Via a negative feedback loop which inhibits GnRH
Other than sperm production, what are the effects of testosterone in puberty?
- The development of secondary sex organs and characteristics
- Increased libido
What is the role of testosterone during aging in males?
-It sustains the male reproductive tract, sperm production and libido
What are the two forms of cell division?
Mitosis and Meiosis
What is Mitosis?
When a body cell doubles its DNA and then divides to produce two genetically identical
daughter cells
What are the four stages of Mitosis? PMAT
- Prophase
- Metaphase
- Anaphase
- Telophase
What is Meiosis?
Cell division that produces four gametes (haploid cells), each with only half the DNA of the diploid body cells
Before prophase in mitosis what is occuring inside the cell?
The DNA is Duplicated and produce sister chromatids
What occurs during mitosis prophase?
Chromatin condenses into chromosomes
What occurs during mitosis metaphase?
Chromosomes line up on the metaphase plate
What occurs during mitosis anaphase?
Sister chromatid’s separate at centromere
What occurs during mitosis telophase?
Cytokinesis occurs
What is the final product of mitosis?
two identical daughter cells
How many phases are there in Meiosis?
8, sames phases of mitosis just doubled
What occurs during meiosis prophase 1?
Chromatins condense into homologue chromosome pairs called tetrads
What occurs during meiosis Metaphase 1?
- Homologue chromosomes line up
- Some cross over and trade DNA
What occurs during Meiosis anaphase 1?
Homologue chromosomes separate
What occurs during meiosis telephase 1?
A new nuclear envelope forms and cells undergo cytokinesis
What occurs during meiosis prophase 2?
No duplication, chromosomes are only 2 cromatids
What occurs during meiosis metaphase 2?
Chromosomes line up
What occurs during meiosis anaphase 2?
sister chromatids separate
What occurs during meiosis telophase 2?
Cytokinesis occurs with the end product being 4 haploid cells with single stranded chromosomes
Spermatogonia divide by ____
Mitosis
What are the products When spermatogonia divide via mitosis?
- Type A spermatogonium
- Type B spermatogonium
What is the function of a Type A spermatogonium?
To remain in the tubule wall as a stem cell
What is the function of a type B spermatogonium?
To migrate away from the wall and begin producing sperm
What becomes of the type B spermatogonium?
It enlarges and becomes a Primary spermatocyte
What is the function of the primary spermatocyte?
To under go meiosis 1 to produce 2secondary spermatocytes
What is the function of the secondary spermatocyte?
To undergo meiosis 2 and produce 2 spermatids
Once spermatids are produced what is the next step?
They undergo spermiogenesis—-transformations and differentiate into spermatozoa(sperm)
What are the three main transformations that a spermatid undergoes to become a spermatozoa?
- Gain a flagellum
- Gain an acrosome
- Lose excess cytoplasm
How are sperm protected form our immune system( since they are genetically different)?
They are surrounded by nurse cells throughout the process of spermiogenesis. The nurse cells protect them from the blood-testis barrier via tight junctions
What are the two parts of a spermatozoon?
The head and tail
What is within the head of the spermatozoon?
- The nucleus
- the Acrosome
What is the function of the acrosome of a spermatozoon?
enzyme cap over the apical half of the nucleus that contains enzymes that penetrate the egg
What are the three regions of the tail of a spermatozoon? along with the general function.
- Midpiece-Coontains mitochondria and produces ATP for flagellar movement
- principal piece- main body
- endpiece- tip
What is the gross composition of semen?
- 60% seminal fluid
- 30% prostatic fluid
- 10% sperm
What is contained within prostatic fluid? CCIP
Milky white
- Citrate
- Clotting enzyme
- Ion buffers
- Prostate-specific antigen: dissolves clot so sperm can continue journey
What is contained within Seminal fluid?
Yellow
- Fructose-nutrient source
- Prostaglandins-Thin mucus plug and stimulate revurse peristalsis
- Proteins for clotting
What are the four phases of coitus (male)?
- excitement
- Plateau
- Orgasm
- Usually with ejaculation
- resolution
What are the two main sources of stimuli to initate the excitment phase?(male)
- Touch
- Vision(or dreams)
excitement Stimuli from touch enter the sacral spinal cord via ____ (male)
The internal pudendal nerve
excitement Stimuli from vision(or dreams) enter the sacral spinal cord via ____ (male)
the brain
Once excitement stimuli is received what occurs next? (results in erection)(male)
- Parasymapthetic fibers in pelvic nerve stimulate release of nitric oxide
- Nitric oxide relaxes deep arteries in corpora cavernosa and relaxes the lacunae
- Lacunae fill and cause an erection
What occurs during the plateau phase?(male)
- Respiratory rate, heart rate, and blood pressures are raised and sustained
- few seconds to few minutes before phase 3
What occurs during the orgasm phase?(male)
-Short intense reaction that usually results in an ejaculation
What are the two phases of ejaculation?
-Emission and expulsion
What occurs during the emmission phase of ejaculation (male)?
Lumbar sympathetic fibers cause:
- Peristalisis of vas defferens
- Secretions from prostate and seminal vesicles
What occurs during the expulsion phase of ejaculation?
-Semen enter urethra and activate somatic and sympathetic reflexes
What are the somatic efferents of the expulsion phase of ejaculation?(male)
Contraction of the bulbocavernosa muscle to expell sperm
What are the sympathetic efferents of the expulsion phase of ejaculation?(male)
- Contraction of the internal urethral sphincter so urine and semen dont mix
- Additional secretions are added
What occurs during the resolution phase? (male)
- Blood flow reduced
- flaccidity occurs
- resp. and heart rate return to normal
- refractory period inhibits erection for minutes to hours
How is erectile dysfunction treated?
- NO activates cGMP which causes blood flow to penis
- ED drugs inhibit the breakdown of cGMP by PDE5
- This increases the amount of available cGMP and allows for and erection
